21828761821 has 8 divisors (see below), whose sum is σ = 23134011264. Its totient is φ = 20525868480.

The previous prime is 21828761807. The next prime is 21828761831. The reversal of 21828761821 is 12816782812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21828761821 - 2²¹ = 21826664669 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21828761831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 569925 + ... + 607018.

It is an arithmetic number, because the mean of its divisors is an integer number (2891751408).

Almost surely, 2^21828761821 is an apocalyptic number.

It is an amenable number.

21828761821 is a deficient number, since it is larger than the sum of its proper divisors (1305249443).

21828761821 is a wasteful number, since it uses less digits than its factorization.

21828761821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1178051.

The product of its digits is 172032, while the sum is 46.

The spelling of 21828761821 in words is "twenty-one billion, eight hundred twenty-eight million, seven hundred sixty-one thousand, eight hundred twenty-one".